/feedreader

Feed Reader is a system which allows users to subscribe/unsubscribe to feeds

Primary LanguageJava

FeedReader

Feed Reader system exposes a set of API's that can be used to create feeds, users and articles. The users can subscribe/unsubscribe to a feed.

Pre Requisites

Maven Installed

JDK 1.8 Version

Installation

git clone https://github.com/srinivas-d-12/feedreader.git
cd feedreader
mvn clean package

Running

Running tests

mvn test

Running application

mvn spring-boot:run

Or

java -jar ./target/feed-reader-1.0-SNAPSHOT.jar

FeedReader API

Endpoint Request Description
/users GET Lists all users
/users POST Add user . Parameters {"name":"user-name", "email":"user@test.com"}
/users/{id} GET Properties of the given user. Includes a link to all the feeds and articles the user has subscribed
/users/{id}/feeds GET Lists all the feeds the user has subscribed
/users/{id}/articles GET Lists all the articles for the feeds the user has subscribed
/users/{id}/feeds PUT Subscribe to a feed. Parameters {"id":"1"} -> feedId
/users/{id}/feeds DELETE Unsubscribe to a feed. Parameters {"id":"1"} -> feedId
/feeds GET Lists all feeds
/feeds POST Add feed . Parameters {"name":"feed-name", "description":"feed-description"}
/feeds/{id} GET Properties of the given feed. Includes a link to all articles
/feeds/{id}/articles GET Lists all the articles that are added to the feed
/feeds/{id}/articles POST Add article to feed. Parameters {"name":"article-name"}
/articles GET Lists all articles
/articles/{id} GET Properties of the given article

Choices

I used spring boot as its easy to create a standalone Java Application, which includes an embedded tomcat server.
It can handle 200 concurrent requests. It reduces the need to write a lot of configuration and boilerplate code.
Due to time constraint, I went with a simple in memory database h2 which has a very small foot print
I have add versioning to each entity so that JPA uses optimistic locking. For persisting the data over restarts, I dump data to disk.
I have kept my model simlple. User <-> Feeds(Many to Many) and Feeds <-> Articles (One to Many).
If the model gets complex, Then I can introduce a subscription Entity class.
For the initial phase, I am not validating if user, feed or article has the same properties. Although each entity will have a generated Id and be treated as a new object.

Future Enhancements

Code

  1. Add Pagination
  2. Display or find by query parameters, Add Deletion of entities.
  3. Handle Duplicates and errors
  4. More comments and tests :P. Never enough

DataBase

  1. Decouple the database layer from the application.
  2. Choose a database that is scalable and highly available.
  3. It needs to be decentralized and elastic.
  4. Choose Casandra or Hbase which can scale

Conflict Handling

  1. Allow the database to handle it. i.e. last-writer wins
  2. Or Streaming approach, sequence of commit logs and rebuild the ordering sequence and merge the logs

High Availablity

  1. Deploy application on n servers based on the load
  2. Add a loadbalancer to distribute the load.

Monitoring

  1. Use springboot actuator to display health metrics
  2. Use Dropwizard codehale metrics/actuator metrics to get metrics on how the application is performing.

Security

  1. Use MTLS so that access is allowed only to users with permission
  2. Can use kerberos too.

RateLimiters

  1. Develop or use rate limiters for unruly clients

Cache

  1. Use memcached or any other caching system to reduce the number of times an external data source (such as a database or API) must be read